Heat exchanger



April 19, 1955 R. R. GRAVES ET AL 2,706,619

HEAT EXCHANGER Filed April 28, 1951 5 Shets-Sheet 1 1? 3Q (IFRK IN VEN T ORS fi y ab April 1955 R. R. GRAVES ETAL 2,706,619

HEAT EXCHANGER Filed April 28, 1951 5 Sheets-Sheet 2 mmvroxs:

April 19, 1955 R. R. GRAVES ETAL 2,706,619

HEAT EXCHANGER Filed April 28, 1951 5 Sheets-Sheet 3 IN V EN TORS-' BY ?0%M% ATTORNE 5.

April 19, 1955 R. R. GRAVES ETAL HEAT EXCHANGER Filed April 28, 1951 5 Sheets-Sheet 5 llllllllllm mmvroxs; 4/ W6 3y $0M? ATTORNEY United States Patent HEAT EXCHANGER Roy R. Graves, Valparaiso, Ind., and Edward K. Kuhles,

Wilmette, Ill., assignors to The Graves-Stambaugh Corporation, a corporation of Delaware Application April 28, 1951, Serial No. 223,482

6 Claims. (Cl. 257-246) This invention relates to heat exchangers.

The principal object of this invention is to provide an improved heat exchanger which is extremely rapid and efficient in operation, which is simple and compact in construction, which is relatively inexpensive to manufacture, which may be readily disassembled for cleaning purposes, which has power operated means for opening up the? heat exchanger for cleaning purposes, which is vertically mounted, which has self-adjusting sealing features preventing leakage, and which is particularly adaptable for use in the food industry for pasteurizing, sterilizing or cooling milk, fruit or vegetable juices or the like.

In this respect the heat exchanger comprises a substantially cylindrical hollow casing having an enclosed heat exchange chamber therein and having a smooth and slightly and uniformly tapered inner surface extending from end to end, and also a substantially cylindrical core longitudinally removably received in the casing, having an enclosed heat exchange chamber therein and having a slightly and uniformly tapered outer surface extending from end to end conforming to the taper of the inner surface of the casing to provide a tight seal between the casing and the core throughout their lengths when the core is received in the casing. A spiral groove is provided in the outer tapered surface of the core to form in conjunction with the casing a spiral passage through which the product to be heated or cooled is circulated.

A ring is removably and longitudinally adjustably carried by the casing and engages the end of the core for forcing the tapered outer surface of the core into sealing engagement with the tapered inner surface of the casing. When the ring is removed, the core may be longitudinally removed from the casing to expose the grooved external surface of the core and the smooth internal surface of the sleeve so that said surfaces may be readily cleaned.

The substantially cylindrical casing is vertically carried by a supporting stand with the wider portion of the tapered inner surface uppermost. A motor also carried by the supporting stand has a connection to the core for vertically raising the core from the casing to a position above the casing for exposing the tapered surfaces for cleaning purposes. By reason of this vertical suspension self alignment between the core and casing is assured without any tendency to cause the mating tapered surfaces to become out of round.

The casing is preferably formed from two sleeve members or tubes which are secured together in spaced rela-.

tion to form the enclosed heat exchange chamber therebetween, the inner sleeve member or tube having the smooth and slightly and uniformly tapered inner surface. The core also preferably includes an outer sleeve member or tube which provides the slightly and uniformly tapered outer surface on the core. The enclosed heat exchange chamber in the core may be formed by the outer sleeve member and an inner sleeve member or tube secured thereto in spaced relation.

Inlet and outlet ports communicate with the enclosed heat exchange chambers for circulating a heat exchange medium, such as steam, water or the like, therethrough. Inlet and outlet ports for the product to be heated or cooled extend through the casing and open into the tapered inner surface of the internal sleeve of the easing near opposite ends of the casing. These inlet and outlet ports register with the ends of the spiral groove "ice in the tapered outer surface of the core to provide a straight through passage for the product to be heated or cooled. This eliminates pockets in which the product might be trapped and this is of great importance in the case of a heater, pasteurizer or sterilizer where the product would become overheated in such pockets.

Interengaging locating means are provided for fixing the rotative position of the core with respect to the casing when the core is received in the casing for registering the ends of the spiral groove with the product inlet and outlet ports communicating therewith.

An annular groove is also provided in the outer tapered surface of the core adjacent each end thereof and beyond the ends of the spiral groove. Deformable resilient O-rings are located in these annular grooves for positively packing the ends of the core and casing without interfering with the tight seal between and throughout the lengths of the two sleeve members.

Further objects of this invention reside in the details of construction of the heat exchanger and the cooperative relationship between the component parts thereof.

Other objects and advantages of this invention will become apparent to those skilled in the art upon reference to the accompanying specification, claims and draw ings, in which:

Fig. 1 is a top plan view of a heater and cooler assembly utilizing two heat exchangers;

Fig. 2 is a side elevational view of the heater and cooler assembly showing the core of the cooler raised above the casing for cleaning purposes;

Fig. 3 is a vertical sectional view of the heater taken substantially along the line 33 of Fig. 2;

Fig. 4 is a vertical sectional view of the cooler taken substantially along the line 44 of Fig. 1;

Figs. 5 and 6 are diagrammatic top plan views of the heater and cooler of Figs. 3 and 4 illustrating the relative positions of the various inlet and outlet ports;

Fig. 7 is a horizontal sectional view taken substantially along the line 7-7 of Fig. 2; and

Fig. 8 is a side elevational view partly in section of a casing for a heater provided with thermal insulation.

Referring first to Figs. 1 and 2, there is disclosed a heater and cooler assembly including a heater generally designated at 10, a cooler generally designated at 11 and a supporting stand for the heater and cooler generally designated at 12. This heater and cooler assembly, although having general utility, is particularly adaptable for pasteurizing or sterilizing milk, fruit or vegetable juices or the like, the heater 10 doing the pasteurizing or sterilizing and the cooler 11 doing the cooling.

The heater 10 is illustrated in more detail in Figs. 3 and 5. The heater includes a substantially cylindrical casing having an outer sleeve member or tube 14 which is secured, as by welding, to flanges 15 on an inner sleeve member or tube 16. The inner surface 17 of the inner sleeve member 16 is smooth and slightly and uniformly tapered from end to end. The wider portion of the tapered inner surface 17 is located uppermost. The flanges 15 space apart the outer and inner sleeve members 14 and 16 to form therebetween an enclosed heat exchange chamber 18.

A fitting 19, having a hole 21 communicating with the enclosed heat exchange chamber 18, is secured, as by welding, to the outer sleeve member 14 near the top thereof for delivering steam, hot water or the like to the heat exchange chamber 18. Likewise, a fitting 20, having a hole 22 communicating with the heat exchange chamber 18, is secured, as by welding, to the outer sleeve member 14 near the bottom thereof for discharging steam or water from the heat exchange chamber 18. In this way heat exchange fluid, such as steam or water, may be circulated through the heat exchange chamber 18 in the casing. A supporting ring 23 is secured to the bottom of the casing, as by welding, and, likewise, another ring 24 is similarly secured to the top of the casing. A fitting 25 is secured to the casing, as by welding, and it extends through the flange portion 15 of the casing and opens into the tapered inner surface 17 of the internal sleeve 16 near the bottom thereof. Another fitting 26, likewise, is secured to the casing and extends through the flange portion 15 and opens into the tapered inner surface 17 of the internal sleeve 16 near the top of the casing. The fittings and 26 form inlet and outlet ports for the product to be heated as, for example, the milk or juices to be pasteurized or sterilized.

The heater also includes a substantially cylindrical core which is longitudinally removably received in the casing. The core may be vertically inserted into the casing and vertically raised therefrom, The core includes an inner sleeve member or tube 28 which is provided at its ends with flanges 29 to which is secured, as by welding, an outer sleeve member or tube 30. The outer surface of the external sleeve member 30 of the core is slightly and uniformly tapered from end to end and conforms to the taper of the internal sleeve member 16 of the casing. When the core is inserted in the casing a tight seal is established between the two sleeve members 16 and 30 throughout their lengths. The outer tapered surface of the sleeve member 36 is provided w1tl1 a spiral groove 31, the ends of the spiral groove terminating at, and in registry with, the inlet and outlet ports 25 and 26, respectively, when the core is received in the casing. This spiral groove 31, cooperating with the inner sleeve member 16 of the casing, forms a spiral passage for the product being heated. Since this spiral passage terminates at the inlet and outlet ports 25 and 26, a straight through passage is provided which eliminates pockets in which the product might be trapped and over heated.

The flanges 29 space apart the inne rand outer sleeve members 28 and 30 of the core to provide therebetween an enclosed heat exchange chamber 32. A fitting 33 is secured, as by welding, to the inner sleeve member 28 and is provided with a hole 34 for introducing a heat exchange medium, such as steam or hot water, into the heat exchange chamber 32, this fitting 33 being located near the top of the core. Another fitting 35 is secured, as by welding, to the inner sleeve member 28 near the bottom thereof and it communicates with the heat exchange chamber 32 for discharging the heat exchange medium therefrom. The fittings 33 and 35, therefore, provide means for circulating a heat exchange medium through the heat exchange chamber 32.

The sleeve members 16 and 30 are relatively thin so that rapid and efficient heat exchange takes place between the heat exchange chambers 18 and 32 and the spiral passage 31 located therebetween. The heat exchange chambers 18 and 32 are completely isolated from each other and from the spiral passage 31 so that there is no danger of the heat exchange medium entering or leaking into the spiral passage containing the product being heated. Because of the tapered surfaces on the casing and the core throughout the length of the casing and the core, a tight seal is at all times maintained therebetween which substantially eliminates leakage of the product from one convolution of the groove 31 to the next convolution and forces the product to flow along the spiral passage. The outer sleeve member 30 of the core is provided with an annular groove 37 near each end thereof and an O-ring 38 of deformable resilient material, such as Neoprene or the like, is located in each of these annular grooves. These O-rings 38 cooperate with the tapered inner surface 17 of the casing for positively packing the ends of the two sleeve members 16 and 30 without in any way interfering with the tight seal between and throughout the lengths of these two sleeve members. In the unlikely event that leakage of the product should occur, the O-rings prevent the product from leaking from the heat exchanger. The O-rings provide self-ad usting sealing means for effectively preventing any leakage of the product being heated.

The casing of the heater 10 is vertically mounted on the supporting stand 12. In this connection, the ring 23 is secured by means of a spacer ring 40 and screws 42 to an upper platform ring 41 of the supporting frame. The platform ring 41 is carried by legs 43 to which is also secured a lower platform 44. The legs 43 may be formed of pipes or tubes, or the like, and secured, as by welding, to the upper platform ring 41 and the lower platform 44. i

The lower platform 44 carries a motor, such as an hydraulic motor. The base 46 of the motor is secured to the platform 44 by means of screws 47 and it carries an upwardly extending cylinder 48. A piston carried by a piston rod 49 reciprocates in the cylinder 48. The upper end of the cylinder 48 is provided with a head 50 for guiding the piston rod 49. The upper end of the piston rod 49 is provided with a screw-threaded extension 51 on which is clamped a hub 52 of a spider by means of a nut 53. The legs 54 of the spider are secured, as by welding, to the upper end of the inner sleeve member 28 of the core. When hydraulic pressure is applied to the motor the motor raises the core vertically from the casing, such vertical position being illustrated at the right of Fig. 2. When the hydraulic pressure is released, the core drops vertically into the casing. By reason of this vertical movement of the core, self-alignment between the core and the casing is assured without any tendency to cause the mating tapered surfaces to become out of round. When the core is thus raised out of the casing, the inner smooth tapered surface of the casing and the outer grooved tapered surface of the core are exposed so that they may be readily cleaned.

The cylinder head 50 is provided with a pin 56 to be received in a hole 57 in the hub 52 of the spider when the core is received in the casing. The pin and hole form interengaging locating means for fixing the rotative position of the core with respect to the casing for registering the ends of the spiral groove 31 with the inlet and outlet ports 25 and 26. A ring 58 is removably and longitudinally adjustably carried by the casing by means of studs 59 secured in the ring 24 and cooperating nuts 60. When the core is received in the casing the ring 58 is applied over the studs 59 and the nuts 60 are then applied to the studs and are tightened to force the core into the casing so as to assure a tight seal between the tapered surfaces of the core and the casing. To elevate the core above the casing, the ring 58 is first removed and then hydraulic pressure is applied to the motor. When the core is so elevated, a pair of sector shaped braces 72, having holes 73, is applied to the upper end of the casing, the holes 73 accommodating the studs 59. These braces 72 are held in place on the studs 59 by the nuts 60 and the inner edges of the braces 72 engage the piston rod 49 for readily supporting the elevated core during cleaning operations. When it is desired to lower the core into the casing, of course, these braces are removed. The braces 72 are illustrated in Fig. 7 and are shown applied to the cooler 11 at the right side of Fig. 2.

The cooler 11 is illustrated in more detail in Figs. 4 and 6 and the construction of the cooler is substantially the same as that of the heater 10 and like reference characters have been utilized for like parts. The essential difference between the cooler 11 and the heater 10 is in the construction of the heat exchange chambers. In this respect, the inner sleeve member 16 of the casing is provided exteriorly with a spiral rib 62 for forming a spiral heat exchange chamber 63. The upper end of this spiral heat exchange chamber 63 terminates at and communicates with a fitting 64 through which a cooling medlum, such as water, may be introduced into the spiral heat exchange chamber. The lower end of the spiral heat exchange chamber 63 is provided with a fitting 65 for discharging the cooling medium.

The outer surface of the inner sleeve member 28 of the core is also provided with a spiral rib 71 for pro- VldlIlg a spiral heat exchange passage 66. The upper end of the heat exchange passage 66 terminates in a fitting 67 for supplying a cooling medium to the heat exchange passage. Likewise, the lower end of the heat exchange passage 66 is provided with a fitting 68 for discharging the cooling medium from the spiral heat exchange passage 66. The product, such as milk, juices and the like, is fed into the spiral groove 31 by means of an upper fitting 69 and is discharged from the spiral groove 31 by means of a lower fitting 70. The fittings 69 and 70 extend through the casing and open into the tapered inner surface of the internal sleeve 16 in registry with the ends of the spiral groove 31. The spiral groove 31 and the spiral heat exchange passages 63 and 66 all run in the same direction and, as illustrated, they are shown to be in affect in the nature of right-hand threads. The spiral passages 63 and 66 operate to prevent Stratification of the cooling medium and thereby provide rapid and efiicient heat transfer. The operation of the cooler, with the exception of the direction of heat transfer, is essentially the same as the operation of the heater.

The cooler 11 is vertically mounted on the supporting frame 12 in the same manner as the heater. The vertical legs 43 of the supporting frame are connected together and braced by transverse braces 75 which also may be made of pipes, tubes and the like, suitably welded to the vertical legs. By mounting the heater and cooler on the common supporting frame they may be cooperatively associated to perform desired processes. For example, the heater may be a pasteurizer or sterilizer for pasteurizing or sterilizing milk and the cooler 11 may be utilized for cooling the pasteurized or sterilized milk. In this. connection, the outlet fitting 25 of the heater may be connected by a relatively large diameter pipe 76 to the inlet fitting 69 of the cooler, this connecting pipe 76 acting as a holding valve. The connecting pipe 76 is provided with a T fitting 77 having a thermometer well for receiving a temperature-responsive device connected to a suitable control instrument by a connection 78. The outlet fitting 70 of the cooler may be connected by a pipe 79 to a diversion valve 80 operated by a motor 81. So long as the temperature of the pasteurized or sterilized milk passing the fitting 77 is maintained at the desired pasteurizing or sterilizing temperature, the thermometer controller operates the motor 81 and, hence, valve 80 to pass the cooled milk through pipe 82 to a suitable bottling or canning mechanism. If, on the other hand, the temperature of the milk at the T fitting 77 should decrease below the desired value, the motor 81 and valve 80 are operated to divert the cooled milk through pipe 83.

Fig. 8 illustrates a casing for a heater which is lagged with thermal insulating material. Here the heater casing is substantially the same as the heater casing of Fig. 3 and like reference characters have been utilized for like parts. In Fig. 8 the rings 23 and 24 are made wider and a thermal insulating material 85 is packed about the outer tubular member 14 between the rings 23 and 24 and a suitable outer shell 86 may be secured to the rings 23 and 24 for maintaining the insulating material 85 in place. The use of this insulating material provides for greater efliciency in operation of the heater.

When the heat exchangers of this invention are utilized for heating or cooling food stuff, such as milk, fruit or vegetable juices or the like, the heaters and coolers are preferably made of non-corrosive metals, such as stainless steel or the like. This not only makes it possible adequately to clean and sterilize the heat exchangers, but it also provides a neat appearance. When the heat exchange assembly is utilized for pasteurizing or sterilizing milk, the milk may be forced through the heater and the cooler under pressure by the homogenizer. As a typical example of the use of the assembly for this purpose, the following dimensions have proven to be very satisfactory: The cores of the heater and cooler are substantially 20.250 inches long and have a diameter of substantially 12.250 inches at the large end and 11.898 inches at the small end. This provides a taper of substantially /2 degree. In the heater the spiral groove 31 is substantially inch wide and substantially inch deep and the spiral groove extends along the core for stantially 16.250 inches. The groove has 32 /2 turns, which provides a 100 foot long groove through which milk passes at a velocity of substantially 24 ft. per second. In the cooler the spiral groove 31 is substantially wide and A" deep and it extends along the core for substantially 17.062". The spiral groove has 19 /2 turns to provide a passage length of substantially 60 feet through which the milk passes at a velocity of 10 ft. per second. Both the heater and the cooler have substantially the same rate of flow of milk therethrough, being about 250 gallons per hour. The milk may be rapidly heated to pasteurizing or sterilizing temperatures by the application of steam to the heat exchange chambers 18 and 32 at normal pressures. Likewise, the milk may be rapidly cooled to suitable temperatures for bottling and canning by supplying water to the heat exchange chambers of passages 63 and 66 at usual tap water temperatures.

Reference is made to copending application Serial No. 223,483, filed April 28, 1951, by Roy R. Graves, and having a portion of its disclosure corresponding to the disclosure of this application. The claims of the copending application are directed generally to the construction of the heat exchanger including the casing, core and clamping ring. The claims of this application include limitations to the O-rings, the locating means for angularly positioning the casing and core, the supporting stand, and the motor means for raising the core vertically from the casing.

While for purposes of illustration one form of this invention has been disclosed, other forms thereof may become apparent to those skilled in the art upon reference to this disclosure and, therefore, this invention is to be limited only by the scope of the appended claims.

We claim as our invention:

1. A separable heat exchanger comprising a substantially cylindrical casing including a casing member and a separate internal sleeve member secured adjacent its ends within the casing member and providing an enclosed annular heat exchange chamber between the casing member and the internal sleeve member, the inner surface of the internal sleeve member being smooth and slightly and uniformly tapered throughout from end to end, a substantially cylindrical core including an external sleeve member and means for providing an enclosed heat exchange chamber within the external sleeve member, the outer surface of the external sleeve member being slightly and uniformly tapered throughout from end to end and conforming to the taper of the internal sleeve member of the casing, said core being longitudinally removably received in the casing and the tapered surfaces of the internal sleeve member of the casing and of the external sleeve member of the core providing the sole means for supporting and seating the core within the casing and providing a tight seal therebetween throughout their entire lengths when the core is received and pressed into the casing, a uniform spiral groove in the outer tapered surface of the external sleeve member of the core having its ends terminating at points spaced inwardly from the ends of the tapered surface within the confines of the tapered surface and forming an enclosed continuous spiral passage between said points which is sealed throughout its length and which is in heat exchange relation with the enclosed heat exchange chambers in the casing and core when the core is received in and pressed into the casing, an enclosed inlet port adjacent one end of the heat exchanger communicating directly with one end of the spiral passage and an enclosed outlet port adjacent the other end of the heat exchanger communicating directly with the other end of the spiral passage to provide pocketless, straight through and uninterrupted flow through the ports and spiral passage, and inlet and outlet ports adjacent the ends of the heat exchanger communicating with the enclosed heat exchange chambers, an annular groove in the outer tapered surface of the external sleeve member of the core adjacent each end thereof and within the confines of the tapered surface between and spaced from the ends of the spiral groove and the ends of the core, and a deformable resilient torroidal O-ring located in each annular groove in the external sleeve member of the core and having a normal thickness greater than the depth of the grooves and being compressed within the confines of the grooves by the internal sleeve member of the casing when the core is longitudinally received in and pressed into the casing for positively packing the sealing engagement at the ends of the two sleeve members without interfering with the tight seal between and throughout the lengths of the two sleeve members.

2. A separable heat exchanger comprising stationary means including a substantially cylindrical casing including a casing member and a separate internal sleeve member secured adjacent its ends within the'casing member and providing an enclosed annular heat exchange chamber between the casing member and the internal sleeve member, the inner surface of the internal sleeve member being smooth and slightly and uniformly tapered throughout from end to end, movable means including a substantially cylindrical core including an external sleeve member and means for providing an enclosed heat exchange chamber within the external sleeve member, the outer surface of the external sleeve member being slightly and uniformly tapered throughout from end to end and conforming to the taper of the internal sleeve member of the casing, said core being longitudinally removably received in the casing and the tapered surfaces of the internal sleeve member of the casing and of the external sleeve member of the core providing the sole means for supporting the core within the casing and providing a tight seal therebetween throughout their entire lengths when the core is received and pressed into the casing, a uniform spiral groove in the outer tapered surface of the external sleeve member of the core having its ends termi- 1ating at points spaced inwardly from the ends of the ;apered surface within the confines of the tapered surface and forming an enclosed continuous spiral passage between said points which is sealed throughout its length and which is in heat exchange relation with the enclosed heat exchange chambers in the casing and core when the core is received in and pressed into the casing, an enclosed inlet port extending through the casing adjacent one end thereof and opening into the tapered inner surface of the internal sleeve member thereof at a point corresponding to one end of the spiral groove in the external sleeve member of the core, an enclosed outlet port extending through the casing adjacent the other end thereof and opening into the tapered inner surface of the internal sleeve member thereof at a point corresponding to the other end of the spiral groove in the external sleeve member of the core, said enclosed inlet and outlet ports registering with and directly communicating with the ends of the spiral passage when the core is received and pressed into the casing to provide pocketless, straight through and uninterrupted fiow through the ports and spiral passage, inlet and outlet ports adjacent the ends of the heat exchanger communicating with the enclosed heat exchange chambers, and interengaging locating means operatively associated with the stationary means and the movable means respectively for fixing the relative rotative positions of the casing and the core when the core is received and pressed into the casing for assuring registration of the enclosed inlet and outlet ports with the ends of the spiral groove directly communicating therewith.

3. A separable heat exchanger comprising a supporting stand, a substantially cylindrical hollow casing having an enclosed heat exchange chamber therein and having a smooth and slightly and uniformly tapered inner surface throughout from end to end, means for securing vertically the casing on the supporting stand with the wider portion of the tapered inner surface uppermost, a substantially cylindrical core having an enclosed heat exchange chamber therein and having a slightly and uniformly tapered outer surface throughout from end to end conforming to the taper of the inner surface of the casing, said core being vertically removably received in the casing and the tapered surfaces of the casing and core providing a tight seal therebetween throughout their lengths when the core is received and pressed into the casing, a spiral groove in the outer tapered surface of the core forming in conjunction with the casing an enclosed continuous spiral passage which is sealed throughout its length and which is in heat exchange relation with the enclosed heat exchange chambers in the casing and the core when the core is received and pressed into the casing, inlet and outlet ports communicating respectively with the ends of the spiral passage and with the heat exchange chambers, a hydraulic motor including a stationary part carried by the supporting stand centrally below the casing and a power driven movable part extending centrally upwardly within the casing and connected to the core for vertically raising the core from the casing to a position above the casing when the hydraulic motor is operated to expose the grooved outer surface of the core and the smooth inner surface of the casing for cleaning purposes.

4. A separable heat exchanger comprising a supporting stand, a substantially cylindrical hollow casing having an enclosed heat exchange chamber therein and having a smooth and a slightly and uniformly tapered inner surface throughout from end to end, means for securing vertically the casing on the supporting stand with the wider portion of the tapered inner surface uppermost, a substantially cylindrical core having an enclosed heat exchange chamber therein and having a slightly and uniformly tapered outer surface throughout from end to end conforming to the taper of the inner surface of the casing, said core being vertically removably received in the casing and the tapered surfaces of the casing and core providing a tight seal therebetween throughout their lengths when the core is received and pressed into the casing, a spiral groove in the outer tapered surface of the core forming in conjunction with the casing an enclosed continuous spiral passage which is sealed throughout its length and which is in heat exchange relation with the enclosed heat exchange chambers in the casing and the core when the core is received and pressed into the casing, inlet and outlet ports extending through the easing and registering and communicating with the ends of the enclosed spiral passage when the core is received and pressed into the casing, inlet and outlet ports communicating with the heat exchange chambers in the casing and core, a hydraulic motor including a stationary part carried by the supporting stand centrally below the casing and a power driven movable part extending centrally upwardly within the casing and connected to the core for vertically raising the core from the casing to a position above the casing when the hydraulic motor is operated to expose the grooved outer surface of the core and the smooth inner surface of the casing for cleaning purposes, and interengaging locating means operatively associated with the stationary and movable parts of the hydraulic motor for fixing the relative rotative positions of the casing and the core when the core is received and pressed into the casing for assuring registration of the inlet and outlet ports with the ends of the spiral groove directly communicating therewith.

5. A separable heat exchanger comprising a supporting stand, a substantially cylindrical hollow casing having an enclosed heat exchange chamber therein and having a smooth and slightly and uniformly tapered inner surface throughout from end to end, means for securing vertically the casing on the supporting stand with the wider portion of the tapered inner surface uppermost, a substantially cylindrical core having an enclosed heat exchange chamber therein and having a slightly and uniformly tapered outer surface throughout from end to end conforming to the taper of the inner surface of the casing, said core being vertically removably received in the casing and the tapered surfaces of the casing and core providing a tight seal therebetween throughout their lengths when the core is received and pressed into the casing, a spiral groove in the outer tapered surface of the core forming in conjunction with the casing an enclosed continuous spiral passage which is sealed throughout its length and which is in heat exchange relation with the enclosed heat' exchange chambers in the casing and the core when the core is received and pressed into the casing, inlet and outlet ports communicating respectively with the ends of the spiral passage and with the heat exchange chambers, a hydraulic motor including a stationary part carried by the supporting stand centrally below the casing and a power driven movable part extending centrally upwardly within the casing and connected to the core for vertically raising the core from the casing to a position above the casing when the hydraulic motor is operated to expose the grooved outer surface of the core and the smooth inner surface of the casing for cleaning purposes and bracing means removably secured to the upper end of the casing and engaging the movable part of the hydraulic motor for bracing the same and the core when the core is raised from the casing for cleaning purposes.

6. A separable heat exchanger comprising a supporting stand, a substantially cylindrical hollow casing having an enclosed heat exchange chamber therein and having a smooth and slightly and uniformly tapered inner surface throughout from end to end, means for securing vertically the casing on the supporting stand with the wider portion of the tapered inner surface uppermost, a substantially cylindrical core having an enclosed heat exchange chamber therein and having a slightly and uniformly tapered outer surface throughout from end to end conforming to the taper of the inner surface of the casing, said core being vertically removably received in the casing and the tapered surfaces of the casing and core providing a tight seal therebetween throughout their lengths when the core is received and pressed into the casing, a spiral groove in the outer tapered surface of the core forming in conjunction with the casing an enclosed continuous spiral passage which is sealed throughout its length and which is in heat exchange relation with the enclosed heat exchange chambers in the casing and the core when the core is received and pressed into the casing, inlet and outlet ports communicating respectively with the ends of the spiral passage and with the heat exchange chambers, a hydraulic motor including a stationary part carried by the supporting stand centrally below the casing and a power driven movable part extending centrally upwardly within the casing and connected to the core for vertically raising the core from the casing to a position above the casing when the hydraulic motor is operated to expose the grooved outer surface Of the core and the smooth inner surface of the casing for cleaning purposes and a ring removably and vertically adjustably carried by the upper end of the casing and engaging the corresponding end of the core for forcibly pressing the core into tight sealing engagement with the casing when the core is received in the casing.

References Cited in the file of this patent UNITED STATES PATENTS 1,046,298 Hurlay Dec. 3, 1912 1,639,051 Munday Aug. 6, 1927 2,445,115 Hanrahan July 13, 1948 2,508,212 Ball May 1, 1950 

